Class: MemCache::Server

Inherits:
Object
  • Object
show all
Defined in:
lib/memcache.rb

Overview

A Multiton datatype to represent a potential memcached server connection.

Constant Summary collapse

ConnectTimeout =

Default timeout for connections to memcached servers.

0.25

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host, port = 11211, weight = DefaultServerWeight) ⇒ Server

Create a new MemCache::Server object for the memcached instance listening on the given host and port, weighted with the given weight.



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# File 'lib/memcache.rb', line 1136

def initialize( host, port=11211, weight=DefaultServerWeight )
	if host.nil? || host.empty?
		raise ArgumentError, "Illegal host %p" % host
	elsif port.nil? || port.to_i.zero?
		raise ArgumentError, "Illegal port %p" % port
	end

	@host 	= host
	@port 	= port
	@weight = weight

	@sock 	= nil
	@retry 	= nil
	@status	= "not yet connected"
end

Instance Attribute Details

#host ⇒ Object (readonly)

The host the memcached server is running on



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# File 'lib/memcache.rb', line 1158

def host
  @host
end

#port ⇒ Object (readonly)

The port the memcached is listening on



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# File 'lib/memcache.rb', line 1161

def port
  @port
end

#retry ⇒ Object (readonly)

The Time of next connection retry if the object is dead.



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# File 'lib/memcache.rb', line 1167

def retry
  @retry
end

#status ⇒ Object (readonly)

A text status string describing the state of the server.



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# File 'lib/memcache.rb', line 1170

def status
  @status
end

#weight ⇒ Object (readonly)

The weight given to the server



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# File 'lib/memcache.rb', line 1164

def weight
  @weight
end

Instance Method Details

#alive? ⇒ Boolean

Test the server for aliveness, returning true if the object was able to connect. This will cause the socket connection to be opened if it isn’t already.

Returns:

  • (Boolean) 


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# File 'lib/memcache.rb', line 1187

def alive?
	return !self.socket.nil?
end

#inspect ⇒ Object

Return a string representation of the server object.



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# File 'lib/memcache.rb', line 1174

def inspect
	return "<MemCache::Server: %s:%d [%d] (%s)>" % [
		@host,
		@port,
		@weight,
		@status,
	]
end

#mark_dead(reason = "Unknown error") ⇒ Object

Mark the server as dead for 30 seconds and close its socket. The specified reason will be used to construct an appropriate status message.



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# File 'lib/memcache.rb', line 1223

def mark_dead( reason="Unknown error" )
	@sock.close if @sock && !@sock.closed?
	@sock = nil
	@retry = Time::now + ( 30 + rand(10) )
	@status = "DEAD: %s: Will retry at %s" %
		[ reason, @retry ]
end

#socket ⇒ Object

Try to connect to the memcached targeted by this object. Returns the connected socket object on success; sets @dead and returns nil on any failure.



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# File 'lib/memcache.rb', line 1195

def socket

	# Connect if not already connected
	unless @sock || (!@sock.nil? && @sock.closed?)

		# If the host was dead, don't retry for a while
		if @retry
			return nil if @retry > Time::now
		end

		# Attempt to connect, 
		begin
			@sock = timeout( ConnectTimeout ) {
				TCPSocket::new( @host, @port )
			}
			@status = "connected"
		rescue SystemCallError, IOError, TimeoutError => err
			self.mark_dead( err.message )
		end
	end

	return @sock
end